Preheat your oven to 400°F. Spray an 9x13-inch baking dish with non-stick cooking spray and set aside.

Slice the kielbasa into ½-inch thick rounds, creating uniform pieces for even cooking.

In a large mixing bowl, whisk together the BBQ sauce, packed brown sugar, Dijon mustard, onion powder, and garlic powder until the sugar dissolves and the mixture is smooth.

Add the sliced kielbasa to the bowl and toss thoroughly to ensure every piece is well-coated with the sweet BBQ glaze.

Transfer the coated kielbasa and all the sauce into your prepared baking dish, spreading pieces in an even layer.

Bake for 30 minutes, stirring once at the 15-minute mark to redistribute the sauce and promote even caramelization.

When the sauce begins to caramelize and looks glossy on the top pieces, remove from oven. Let cool for 5 minutes before serving to allow the glaze to set. If desired, add the glazed slices to a small slow-cooker on the warm setting if making these for a party.